This invention relates generally to internal combustion (I.C.) engine intake systems, and in particular it relates to a novel wave deflector for use in tuned runners to the individual cylinders.
A known construction for an I.C. engine intake system comprises the use of tuned runners leading to the individual cylinders and wave deflectors disposed in association with the runners. In general it may be said that the wave deflectors are selectively operable to de-select a particular set of runners under certain operating conditions so that air is conducted to the cylinders through a differently tuned set of runners. If independently operable wave deflectors are provided in association with each set of runners, each such set can be independently de-selected. A wave deflector is poised at the cylinder end of a runner. It is operable to open and closed positions, opening and closing the associated runner. De-selection of a runner occurs when the corresponding wave deflector is closed. A closed wave deflector blocks, or deflects, the pressure wave that emanates from the corresponding cylinder when the piston within the cylinder is executing the intake stroke.
The known construction for a wave deflector comprises a metal shaft that passes through aligned circular holes in walls separating the runners which extend to adjacent cylinders. Metal blades that form the deflectors are fastened to the shaft. This construction is expensive because it uses a number of individual parts and requires a significant amount of assembly. Moreover, if one of the parts should break away, it could enter the engine cylinder and create undesired consequences.
The present invention arises in part through the recognition that a precise fit of a wave deflector to an associated runner is not essential for the purpose of accomplishing the wave deflection function. In other words, when a wave deflector is closed, it is not essential that the edge of the wave deflector be perfectly sealed with respect to the wall of its runner. Accordingly, the invention contemplates a wave deflector fabricated from a plastic material, and furthermore, a pair of wave deflectors that are integral with the shaft so that as a result, the wave deflectors and shaft constitute a single part or element.
A further attribute of the invention is that suitable plastic materials can make this one-piece wave deflector element resiliently bendable so that it can be installed more expediently than the prior multiple metal piece construction referred to previously. The disclosed plastic wave deflector element also has slots between the wave deflectors and the shaft that facilitate bending during the installation process.
The disclosed wave deflector element spans the runners to two adjacent cylinders. The ends of the element are part of the shaft, and they are fitted to circular holes in respective walls of the runners. The runners share a common wall, and an intermediate portion of the element's shaft must pass through this common wall. In order to acceptably, and conveniently, accommodate this intermediate portion of the shaft, the common wall comprises a slot. A clip that journals the intermediate portion of the shaft is fitted to this slot. The shaft, the clip, and the slot are constructed and arranged such that the wave deflector element is accurately axially located and there is substantial closure of the slot between the two adjacent runners so that there is no cross flow between these runners.
Other related features of the invention are: the formation of an integral sealing lip on the element to seal its journaling in the runner walls; an integral provision for creating an eccentric by which the element can be actuated; a detent mechanism for favoring the open and closed positions as two discrete positions of rotation of the element; and the method of installing the element.
The foregoing, along with additional features, advantages and benefits of the invention will be seen in the ensuing description and claims which should be considered in conjunction with the accompanying drawings. The drawings disclose a presently preferred embodiment of the invention according to the best mode contemplated at this time in carrying out the invention.